Prematurity and its complications are the leading causes of death among children in the first year of life and causes of morbidity lasting for the entire lifespan. Premature and very low birth weight infants (PVLBW, defined as gestational age d 32 weeks and birth weight d 1500g) are 100 times more likely than a normal infant to die in the first year of life, and they are at high risk for developmental delays, functional disabilities, and often have multiple complex chronic conditions affecting the lungs, gut, brain, eyes, and other organs. Specifically, PVLBW children are at high risk for bronchopulmonary dysplasia (BPD), necrotizing enterocolitis (NEC), and intraventricular hemorrhages (IVH). We propose to conduct an epidemiologic description of the co-occurrence of these conditions, through a secondary analysis of 15470 premature children admitted to NICUs from 2006- 2010 at 33 children's hospitals in the Pediatric Health Information System (PHIS) database, looking at the effects of these chronic conditions on PVLBW infants receiving care in NICUs. The outcomes of interest include death during the NICU stay, cumulative burden of therapies received during the NICU stay, and re- hospitalization within 30 days following discharge from the NICU. We will: 1) Describe the incidence of the chronic conditions among PVLBW infants during the initial NICU admission, singly and in combination. 2) Describe the associations between the chronic conditions, singly and in combination, and three outcomes of the first NICU admission: death during the NICU stay, the cumulative burden of therapies received during the NICU stay, and re-hospitalization following discharge from the NICU. 3) We will document the consequences of one key intervention on the outcomes: the use of inhaled Nitric Oxide to prevent and treat BPD. The rates of both prematurity and VLBW are rising in the U.S. VLBW occurs at >2.5 times the rate among blacks compared to the rest of the U.S. population and is therefore a significant vector of health disparities. In all analyses, we will look for evidence of disparate incidence, outcomes, treatment or efficacy of treatment of the chronic conditions based on race or payer status. We will also look for hospital- or region-specific variation in the incidence, outcomes, or treatment of the chronic conditions. Because PVLBW babies are often subject to multiple chronic disorders and are over-represented in an underserved community, they are a priority population for comparative effectiveness research. The proposed study will be significant because it will be the first to systematically describe, in a large sample, the incidence, outcomes, and treatment of multiple co- occurring severe chronic conditions in PVLBW infants, a population experiencing significant mortality and morbidity. PUBLIC HEALTH RELEVANCE: PROJECT NARRATIVE Premature and very low birth weight (VLBW) infants are at high risk for death, developmental delays, functional disabilities, and often have multiple complex chronic conditions, including bronchopulmonary dysplasia (BPD), necrotizing enterocolitis (NEC), and intraventricular hemorrhages (IVH). We propose to conduct an epidemiologic description of the co-occurrence of these conditions, through a secondary analysis of 15470 premature children admitted to NICUs from 2006-2010. The outcomes of interest include death, cumulative burden of therapies received, and re-hospitalization within 30 days following NICU discharge. Prematurity and VLBW are rising in the U.S. VLBW occurs at >2.5 times the rate among blacks and is therefore a significant vector of health disparities. Because PVLBW babies are often subject to multiple chronic disorders and are over-represented in an underserved community, they are a priority population for comparative effectiveness research.